More than 20,000 New Zealand children have a parent in jail and those youngsters are up to seven times more likely to end up as prisoners, a child charity says.

But new initiatives including more child-friendly prisons could help cut the numbers.

Pillars, a charity which supports prisoners' children and their families and is marking Children of Prisoners Week, commissioned a two-year study which looked at the the needs of inmates' youngsters. It found 23,000 children had a parent in jail. The charity interviewed 271 prisoners and 74 children and whanau members.

Contrary to a belief that children of prisoners should be kept away from their incarcerated parent because of a fear they'd be normalised to the culture, the study found children and prisoners can benefit from contact.

The research found no evidence to support "normalisation" of prison culture being a cause of inter-generational crime. A more likely cause was the economic and social circumstances of the families.

"Most of these children live in conditions of significant poverty, where their basic needs struggle to be met. Families endure these effects, and are resigned to the children, in many cases, getting into trouble."

Pillars employs social workers to support whanau and runs a mentoring programme for children of prisoners, but chief executive Verna McFelin also stresses the importance of strong family relationships for children.

"Parent-child bonding is a critical component for child wellbeing ... It's the separation of the child from their parent that actually does the damage."

Pillars recommends the Corrections Department introduce free methods of communication between inmates and families, make the visiting process as pleasant and friendly as possible and ensure prisoners are good parents even while in prison.

Yesterday, the Herald visited Mt Eden Corrections Facility. Since May last year its visiting rooms have featured bright play areas for children.

Parents are also given the opportunity to buy $1 Kiddie Packs filled with nutritional food, as children have often had up to an hour's wait before seeing their parent at the prison.

Prisoners aren't permitted in the windowed rooms which are off the main visiting area, but the kids can come and go between the two freely.

Prison director Steve Hill said the changes enabled fathers to read to their children, giving them bonding time and increased literacy.

If parents had a difficult discussion to have around finances or family life, the children could occupy themselves.

The new rooms had led to calmer more relaxed visits and had a flow-on effect on prisoner behaviour, he said.

A sentence for all the family

A Christchurch mum says the imprisonment of her ex-partner on a drugs charge created anger problems for her son and it was only with outside help that she was able to turn both their lives around.

Vanessa's son and her ex-partner bonded in the year before jail. The cut in access over the year-long sentence six years ago sent her son, then 12, into a tailspin. He started running away, became violent and once had to be talked down from the roof of their house after climbing up with a knife. He was 13.

"He became a really angry boy. I was pretty close with the youth aid officer - he was like a close friend because I saw him so often. I honestly thought he [her son] was going to end up in jail or dead."

Pillars, a charity that supports children and whanau of prisoners, got involved in her life three years ago. It gave her more confidence as a parent.

The decision to kick her son out was difficult, but one that saw him move into a home with strong male role-models. The space has allowed them to develop a loving relationship.

And for the past year her son has kept out of trouble.

This week, which is Children of Prisoners Week, Vanessa spoke about her family's experience at a Pillars fundraiser. "Not My Crime - Still My Sentence" is the week's theme and it's a sentiment that rings true for her.

Locked up

8649 Total prison population

8134 Male515 Female

Ethnic breakdown

51 per cent Maori32.9 per cent European11.7 per cent Pacific Island2.7 per cent Asian1.7 per cent Other